Had me hair tearing for a couple of hours. Hope this saves your hair!
Post SP2 update –
Symptoms
IE doesn’t interpret CSS pages
Javascript does not work on pages with Javascript (VBS doesn’t work either but you don’t see much)
Pages with ASP content error and give page not found
HELP – ABOUT IE – no version number or cipher strength information showing
Answer
Re-install Windows Scripting Host version 5.6 which you can download from MS by searching for it in the Knowledge Base.
Re-installing SP2 which is a generic MS suggestion for this sort of thing does NOT work